diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8cdffcb..c932ad9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,13 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 (modification: no type change headlines) and this project adheres to
 [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [1.2.1] - 2019-06-03
+
+- Added `Istanbul` HF candidate [EIP-1108](https://eips.ethereum.org/EIPS/eip-1108)
+  (`DRAFT`) updated `alt_bn128` precompile gas costs (see `hardforks/istanbul.json`)
+
+[1.2.1]: https://github.com/ethereumjs/ethereumjs-common/compare/v1.2.0...v1.2.1
+
 ## [1.2.0] - 2019-05-27
 
 **DRAFT Istanbul Hardfork Support**
diff --git a/README.md b/README.md
index 32ab7ff..cb9b0dc 100644
--- a/README.md
+++ b/README.md
@@ -62,6 +62,8 @@ to ease `blockNumber` based access to parameters.
 
 # Hardfork Params
 
+## Active Hardforks
+
 There are currently parameter changes by the following past and future hardfork by the
 library supported:
 
@@ -73,7 +75,19 @@ library supported:
 - `byzantium`
 - `constantinople`
 - `petersburg` (aka `constantinopleFix`, apply together with `constantinople`)
-- `istanbul` (`DRAFT`)
+
+## Future Hardforks
+
+Scope and technical details on the `Istanbul` HF are currently forming out
+within [EIP-1679](https://eips.ethereum.org/EIPS/eip-1679) respectively the
+associated EIP pages.
+
+Supported EIPs in the library:
+
+- [EIP-1108](https://eips.ethereum.org/EIPS/eip-1108) `alt_bn128` precompile
+  gas cost reductions (HF candidate, `DRAFT` status)
+
+## Parameter Access
 
 For hardfork-specific parameter access with the `param()` and `paramByBlock()` functions
 you can use the following `topics`:
diff --git a/package.json b/package.json
index 829f161..93c4746 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ethereumjs-common",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "Resources common to all Ethereum implementations",
   "main": "./dist/index.js",
   "types": "./dist/index.d.ts",
diff --git a/src/hardforks/istanbul.json b/src/hardforks/istanbul.json
index 665ccd6..4aed73d 100644
--- a/src/hardforks/istanbul.json
+++ b/src/hardforks/istanbul.json
@@ -6,7 +6,24 @@
     "status": "Draft"
   },
   "gasConfig": {},
-  "gasPrices": {},
+  "gasPrices": {
+    "ecAdd": {
+      "v": 150,
+      "d": "Gas costs for curve addition precompile"
+    },
+    "ecMul": {
+      "v": 6000,
+      "d": "Gas costs for curve multiplication precompile"
+    },
+    "ecPairing": {
+      "v": 45000,
+      "d": "Base gas costs for curve pairing precompile"
+    },
+    "ecPairingWord": {
+      "v": 34000,
+      "d": "Gas costs regarding curve pairing precompile input length"
+    }
+  },
   "vm": {},
   "pow": {},
   "casper": {},